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© Tim Scrivener New research has found that growing cover crops and reducing cultivations can triple earthworm numbers, resulting in healthier soil. Earthworms are a key indicator of soil
health as their activity offers many benefits, including greater nutrient availability, improved drainage and enhanced soil structure, all of which help to maximise yields. Many observations
have suggested cover crops can promote worm numbers, however, research from Cranfield University has now quantified this increase. The trial investigated the impact of a cover crop mixture
planted in a wheat-maize-lettuce rotation on lowland peat soils at a Cambridgeshire farm between 2016 and 2019. Researchers established a cover crop mixture comprising mustard, oilseed
radish and black oat. Measurements of earthworm abundance, soil nitrogen and moisture levels were taken at two separate times; after the cover crop was planted between wheat and maize
planting and between maize and lettuce planting. They found that earthworm populations were three times greater after the cover crop compared with a treatment without any vegetation from
cover crops. “The continuous vegetation provided by the cover crop combined with reduced tillage, resulted in a huge increase of earthworms,” said Tom Storr, researcher at Cranfield
University. Dr Storr also pointed out that the benefits of the cover crop were particularly notable when they were grown for a longer period. Results also showed that earthworm numbers are
adversely affected by soil cultivations, so reducing the depth and intensity of tillage can promote their communities to aid soil structure, water infiltration and nutrient availability.